Door drive and lock for a mass transit vehicle

ABSTRACT

A power door operator for mounting overhead of a door opening in a mass transit vehicle for moving a door panel over and away from the door opening, including a base plate incorporating a rotary helical drive internal of a door hanger. The door panel is locked in a closed position by primary and secondary means preventing drive rotation and panel movement.

CROSS REFERENCE TO RELATED APPLICATION

This application for patent is a division of application Ser. No.08/804,779, filed Feb. 24, 1997.

BACKGROUND OF THE INVENTION

This invention relates generally to car door operators for mass transitvehicles, more particularly concerning operators mounted overhead of adoor opening in the vehicular side wall. The invention disclosed hereinfurther relates particularly to power door operators incorporatinghelical drive/nut components and incorporating independent primary andsecondary panel locks through prevention of drive member rotation anddirect prevention of panel motion.

Overhead door operators incorporating helical drive members are wellknown in the field of mass transit door equipment. U. S. Pat. Nos.3,745,705; 4,198,786; and 5,341,598 disclose overhead operators. All ofthe above mentioned operators utilize exposed helical door drive andexposed, axially displaced door hangers. In these arrangements there isa substantial force couple generated by offsetting the door drive anddoor hanger, thereby increasing wear on both the drive nut, hanger andany associated door panel lower guides. In addition, the physicaldisplacement between the drive member and door hanger results incritical limited adjustment of the door panel with regard to motiontransverse to the panel plane and hanger axis. Further, the exposedhanger and helical drive/nut combinations are particularly susceptibleto contamination present in the application, including wear and dirtparticles. Atmospheric corrosion is also a substantial problem.

The invention disclosed herein largely overcomes the difficultiesthrough the use of a coaxial design wherein the helical drive member isdisposed internal of and coaxial with a semi-cylindrical door hanger.This arrangement minimizes the force couple generated by the drivemember--door panel spacing or offset. In addition, the door hangerutilizes upper and lower plastic rollers operating on the correspondingsurfaces of the semi-cylindrical hanger. This arrangement greatlyreduces the criticality of transverse door adjustment.

Also, a part of the invention disclosed herein is a greatly simplifieddoor panel lock incorporating a ratchet cam and lock pawl combinationwhich provides unidirectional rotation of the helical member. Thisallows precision positioning of the panel and prevents back driving thedoor panel through reverse rotation of the helix. The lockingarrangement further includes a projection of the lock pawl through aslot or aperture in the door hanger whereby door panel opening motiondue to a failure in engagement of the lock pawl and ratchet cam will beprevented by the continuing presence of the lock pawl in theaforementioned hanger slot. The design, therefore, provides trulyindependent primary and secondary door panel locks.

Therefore, it is an object of the invention to provide an overhead powerdoor drive having inherent primary and secondary door panel locks.

It is an additional object of the invention to provide a power doordrive having coaxial hanger and drive members minimizing door drive/doorpanel offsets and attendant wear producing forces.

It is a further object of the invention to provide a power overhead doordrive wherein the helical drive member is completely contained within asemi-cylindrical hanger, thereby minimizing environmental andatmospheric contamination of the helical drive/nut engagement.

It is a further object of the invention to provide an overhead doordrive wherein the coaxial relationship between a helical drive memberinternal of a semi-cylindrical door hanger utilizing cylindricallyconcave rollers intermediate the door panel and hanger surface providessimplified adjustment of the driven door panel.

SUMMARY OF THE INVENTION

The door drive disclosed herein includes a base plate mounted overheadof an opening in the side wall of a mass transit vehicle. The base plateincludes a semi-cylindrical door panel hanger portion. Mounted internalof the base plate hanger portion is a helical drive including a threadedcylindrical member and cooperating drive nut of the recirculating balltype. The helical drive member is rotated by a rotary prime movermounted at one end of the base plate. The opposite end of the helicaldrive member is journaled internal of the hanger portion of the baseplate in a cylindrical roller bearing.

The drive nut extends through a longitudinal slot in the hanger portionof the base plate for reciprocal motion therein, on rotation of therotary prime mover corresponding to said motion. A door bracket affixedto the upper end of a door panel is connected to the above mentioneddrive nut extension. The door bracket further includes at least two setslongitudinally disposed vertically oriented pairs of cylindricallyconcave plastic rollers. The aforementioned vertical orientationprovides upper and lower rollers in each pair. In operation, the upperand lower door bracket rollers cooperate with corresponding services inthe semi-cylindrical hanger portion of the overhead mounted base plate,thereby providing low friction contamination resistant movement of thedoor panel when the rotary prime mover is energized and rotates thehelical drive member. The combination provides reciprocal travel of thedrive nut and attached door panel on the hanger portion of the baseplate.

Locking of the door panel in a closed position is accomplished throughthe use of a ratchet cam rotating on the helical drive member and anassociated lock pawl. The lock pawl passes through an aperture in theabove-described door bracket, contacting the ratchet cam such that onlyunidirectional rotation of the cam is allowed with the lock pawl inplace. Therefore, with the door panel in a closed and locked position,the lock pawl occupies a position internal of a slot in the door panelbracket. In this condition the lock pawl and ratchet cam preventrotation of the helical member which would allow panel movement in anopening direction on back driving of the drive nut and helical member.However, since the position of the lock pawl in the door panel bracketslot is independent of lock pawl/ratchet cam engagement, movement of thedoor panel in an opening direction should said engagement fail,continues to be prevented.

The above described combination of lock pawl/ratchet cam and location ofthe lock pawl provide separate and distinct primary and secondary locksfor the door panel in that a failure of the ratchet cam/lock pawlengagement or other failure allowing rotation of the helical drivemember with attendant motion in the opened direction of the door panelis prevented by the presence of the lock pawl in the door bracket slot.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and advantages of the invention will become apparent uponreading the following detailed description and upon reference to thedrawings in which:

FIG. 1 is a partial perspective view of a typical transit car body,particularly showing location of the operators of the invention in placeoverhead of reciprocating car door panels;

FIG. 2 is a partial perspective view of one operator shown in FIG. 1,particularly showing location of the door panels, and other operativecomponents of the power door drive through cut-away views;

FIG. 3 is a partial perspective view of the lock pawl and ratchet camutilized in the invention, and, as indicated in the dashed circle ofFIG. 2 and identified by numeral 3;

FIG. 4 is an exploded view of the drive members, lock shaft, lock panel,and door bracket of the invention.

FIG. 5 is a further partial perspective view of the operator of theinvention including a tearaway view of the drive member and drive nut,and particularly showing the opposite side of the operator of FIG. 2;

FIG. 6 is a partial plan view of the operator of the invention,particularly showing the lock shaft and lock members.

FIG. 7 is a section of the operator of the invention the along lines7--7 of FIG. 6;

FIG. 8 is a section of the operator of the invention along the lines8--8 of FIG. 6;

FIG. 9 is a section of the operator of the invention along the lines9--9 of FIG. 6;

FIG. 10 is a partial section of the operator of the inventionparticularly showing end view of the lock and unlock cams;

FIG. 11 is a view along the lines 11--11 of FIG. 10, particularlyshowing a plan view of the lock cam and lock shaft of the invention;

FIG. 12 is an additional partial section of the lock assembly of theinvention, particularly showing the position of a lock pawl in anunlocked position;

FIG. 13 is a partial plan view of the lock assembly of the invention,particularly showing the lock shaft pawl and lock cam with the door in apartially closed position;

FIG. 14 is a partial section of the lock assembly of the inventioncorresponding to the door position of FIG. 13;

FIG. 15 is a partial plan view of the lock assembly of the invention,particularly showing the door in a fully closed position;

FIG. 16 is an additional partial section of the lock assembly of theinvention with the panel as shown in FIG. 15;

FIG. 17 is a partial section of the invention, particularly showing themanual unlocking assembly of the invention, particularly showing thelock shaft in a manually unlocked position;

FIG. 18 is an additional plan view of the manual unlock assembly of FIG.17; and

FIG. 19 is a partial perspective view of the drive system of theinvention, particularly showing the rotary drive member, shaft couplerbetween the rotary prime mover and the helical drive member and the lockpawl/ratchet cam in engagement.

While the novel concentric overhead power door actuator of the inventionwill be described in connection with a preferred embodiment and a singlealternate embodiment, it will be understood that it is not intended tolimit the invention to those embodiments. On the contrary, it isintended to cover all alternatives, modifications and equivalents thatmay be included within the spirit and scope of the invention disclosedand defined by the appended claims.

DETAILED DESCRIPTION OF OPERATION:

With respect to FIG. 1, there is shown a partial view of a "typical"transit vehicle having bi-parting doors 4 and 5 having covered windows 6and 7 driven by power operators 10 and 13 for reciprocal motion over andaway from an opening 2 in car 1.

Mounted overhead of door panels 4 and 5, operators 10 and 13 provide theabove-mentioned reciprocal motion. As operators 10 and 13 are identical,the following description will be concerned with operator 13 as thoseskilled in the art will readily understand that operation of operatorassembly 10 is identical other than the direction of motion.

Operator 13 includes a base and hanger assembly 16 having a base portion18 and a hanger portion 21. Hanger portion 21 includes an internalcavity 23 and a longitudinal slot 20. Surrounding the internal cavity 23of the hanger portion 21 there are upper and lower hanger surfaces 22and 25, respectively.

As shown in FIGS. 7 and 8, the base plate 16 mounts in housing 12attached to car member 11. Helical drive member 36 is rotatably mountedin cavity 23 using drive motor 37 at one end coupled to helical member36 via coupler 38. The distal end of helical member 36 is supported byoutboard cylindrical roller bearing 39 journaled internal of the cavity23 (not shown). Drive nut 40 (Reference FIG. 5) may be of the well knownrecirculated "ball nut type" mounted on drive member 36 for reciprocalmotion along said drive member on rotation thereof.

The cavity 23 of hanger portion 21 of the base plate 18 further includesa longitudinal slot 20. Nut 40 includes a protrusion 43 extendingthrough the slot 20. Protrusion 43 is affixed to the panel bracket 17portion of hanger assembly 28.

Turning now to FIGS. 2, 5 and 7, the hanger assembly 28 carrying thedoor panel 4 includes upper rollers 31 and lower rollers 34 rotatablyattached to the panel bracket 17. Rollers 31 and 34 cooperate withsurfaces 22 and 25 in providing motion along the hanger portion 21 ofbase plate 16.

Protrusion 43 of drive nut 40 extends through slot 20 and is attached topanel bracket 17 intermediate the attachment points of rollers 31 and 34(Reference FIGS. 5 and 7). Motion of drive nut 40 attached to doorbracket 17 via protrusion 42 moves the door panel 4 on rotation ofhelical member 36.

In further reference to FIGS. 4 and 6, lock shaft assembly 53 isrotatably attached to the internal surface of the upper portion 18 ofbase plate 16. Mounting of assembly 53 is accomplished by journaling theshaft 56 in journals 59 for rotatably motion therein. Also attached toshaft 56 is lock pawl 49, unlock tab 62, and lock cam 65, as shown. Theshaft 56 is maintained in a counterclockwise position by torsion spring60. The combination of spring 60 and lock pawl 49 when occupying slot 44in hanger 17, cooperating with ratchet wheel 45, provide unidirectionalrotation of helical shaft 36, thereby preventing clockwise rotation ofhelical shaft 36. Operation of ratchet wheel 45 and lock pawl 49 couldbe achieved through use of a unidirectional clutch.

Also attached to the upper inner surface of base assembly 16 is lockpanel assembly 71 including lock panel 75 (Reference FIGS. 4 and 7). Inposition, lock panel 75 carries unlock solenoid 74, lock cam 68, panelsensor 72 and manual unlock assembly 77. The operation of this panelwill be described further in substantial detail.

In operation, rotation of helical member 36 by drive motor 37 movesdrive nut 40 in a direction dependent on the rotation of member 36. Thefollowing description will assume that the door panel is in a closed andlocked position, as shown in FIG. 6. Operation of the novel lock shaftconfiguration 53 is best seen with reference to FIGS. 10 through 16.

In the closed and locked position, lock cam 68 biased by spring 70 hasallowed lock shaft 56 to assume a somewhat counterclockwise positionwherein lock pawl 49 and ratchet wheel 45 are in a 4ondition shown inFIGS. 3, 5 and 16, whereby further rotation in a clockwise (dooropening) direction is prevented by the interaction of ratchet wheel 45and lock pawl 49. Lock pawl 49, lodged in aperture 44 in door hanger 17,further prevents motion of door panel 5. As shown in FIGS. 15 and 16,lock cam 68 pivoted at 69 is biased counterclockwise by spring 70. Withthe pin 42 in a door closed position, cam 68 and lock shaft cam 65 aredisengaged (Reference FIG. 15).

On receipt of a door open command, solenoid 74 is energized raising thesolenoid plunger 76, contacting tab 62, thereby rotating shaft 56 in acounterclockwise direction, as shown in FIG. 10. Rotation of shaft 56raises cam 65, thereby withdrawing lock pawl 49 from slot 50 in panelbracket 17 (Reference FIG. 12). Separation of lock pawl 49 and ratchetwheel 45 unlocks the ratchet wheel 45, allowing helical shaft 36 torotate in a clockwise direction. The position of lock pawl 49 is sensedby projection 52 and sensor 51, thereby energizing drive motor 37,rotating helical member 36 in a clockwise direction. Rotation of member36 moves drive nut 40 and door panel 5 to an opened position.

Operation from a fully opened position to closed and locked proceeds asfollows:

With particular reference to FIGS. 10 through 16.

With the door in a fully opened position, cam 68 is in the positionshown in FIG. 11 wherein cam 68 has contacted lock cam 65, therebyrotating lock shaft 56 counterclockwise. In this condition, lock pawl 49is rolled out of engagement with ratchet wheel 45 and outside of slot 50as shown in FIG. 12.

To initiate a closing cycle, drive motor 37 rotates helical drive member36 in a clockwise direction thereby moving door bracket 42 toward thefully closed position. When pin 47 attached to bracket 42 reaches thelower portion of lock cam 68, lock elements are as shown in FIG. 11.Further movement of lock pin 47 rotates lock cam 68 in a clockwisedirection due to the novel spatial relationship between lock pawl 49,lock shaft cam 65 and hanger slot 44, as signaled by panel sensingswitch 72, and panel bracket 73, motion of door panel bracket alignsslot 44 and lock pawl 49. Rotation of lock shaft 56 simultaneouslyallows lock pawl 49 to enter slot 44, and engage ratchet wheel 45. Atthis point, both the primary lock, i.e., lock pawl 49 and ratchet wheel45, and the secondary lock, i.e., lock pawl 49 in slot 44, are engaged,as shown in the progression of FIGS. 13, 14, 15 and 16. Movement of lockpawl 49 into slot 50 is detected by sensor 51 as is the location ofpanel bracket 42 by sensor 72 and tab 73.

Those skilled in the art will readily see that with the lock pawl 49 inslot 50 and held against ratchet wheel 45, the door panel 5 is held in aclosed position, requiring two consecutive failures, i.e., a failure ofthe ratchet wheel 45 and lock pawl 49 acting in slot 50 to allowunauthorized door opening. This novel approach provides primary andsecondary door panel locks in a single package, providing anextraordinarily high level of reliability in the locked position.

Operation of the manual unlocking assembly 77 proceeds as follows. Withthe door in the above described closed and locked position, in the caseof loss of power, manual unlocking is achieved by downward force onlever 81, thereby rotating cam 79 against toggle spring 83. Rotation ofmanual unlock cam 79 in a counterclockwise direction contacts unlock cam65, rotating shaft 56, thereby moving lock pawl 49 out of engagementwith ratchet wheel 45 and slot 50 in hanger bracket 17. At this point,the door can manually be moved to an opened position.

Thus, it is apparent that there has been provided in accordance with theinvention a linear overhead power door operator having asemi-cylindrical hanger and an internally mounted coaxial door drivemember that fully satisfies the objects, aims and advantages as setforth above. While the invention has been described in conjunction witha specific embodiment thereof, it is evident that many alternatives,modifications, and variations will be apparent to those skilled in theart in light of the foregoing description. Accordingly, it is intendedto embrace any and all such alternatives, modifications and variationsas may fall within the spirit and broad scope of the appended claims.

What is claimed as new and desired to be secured by Letters Patent ofthe United States is:
 1. A lock operable by a power door operator formaintaining a door panel in a closed position over an opening in a masstransit vehicle, said power door operator having:a door hanger mountableoverhead of said opening; door drive means internal said hanger, saiddoor drive means including a rotary helical drive member havingmechanical connection to a motor and a cooperating drive nut providingreciprocal motion of said drive nut over and away from said opening, onrotation of said helical drive member; a door panel bracket attachableto said door panel, said door panel bracket mounted for movement on saidhanger, said door panel bracket attached to said drive nut; said lockcomprising: a ratchet wheel having mechanical connection to said helicaldrive member; a lock pawl actuable to engage said ratchet wheel toprevent rotation of said helical drive member when said door panel is insaid closed position to provide primary locking of said door panel; andsaid lock pawl, when actuated to engage said ratchet wheel, furtherengaging said door panel bracket to provide secondary locking of saiddoor panel.
 2. In combination, an overhead power door operator formoving a door panel from open to closed and closed to open positionsover a door opening in a mass transit vehicle and a door lock forholding said panel in said closed position, said combinationcomprising:a base and hanger unit mountable overhead of and across saidopening, said base and hanger unit having a hanger portion, said hangerportion including a longitudinal cavity; a longitudinal slot in saidcavity; a helical door drive mounted in said cavity and journaled forrotation therein, said helical door drive having a rotary helicalthreaded shaft and cooperating drive nut, said drive nut having aprotrusion extending through said slot; a motor on said base and hangerunit, said motor having mechanical connection to said helical door drive; a bracket attachable to said door panel, said bracket mounted on saidhanger portion of said base and hanger unit for motion therealong; saidprotrusion of said drive nut attached to said bracket so that rotationof said helical door drive by said motor moves said door panel from saidopen position to said closed position over said opening; means attachedto said base and hanger unit for preventing rotation of said helicaldoor drive on movement of said door panel to said closed position toprovide primary locking of said door panel, said bracket coacting withsaid means for preventing rotation of said helical door drive to preventmovement of said bracket to provide secondary locking of said doorpanel.
 3. The combination of claim 2 wherein said means for preventingrotation of said helical door drive includes:a ratchet wheel attached tosaid helical drive; and a lock pawl pivotally attached to said base andhanger unit to engage said ratchet wheel to prevent said rotation ofsaid helical drive.
 4. The combination of claim 3 wherein said bracketincludes a bracket slot; andso that in a door closed position, said lockpawl enters said bracket slot, thereby preventing door panel movementaway from said door closed position to provide said secondary locking ofsaid door panel.